\psset{unit=1, algebraic=true}
\begin{pspicture*}(-4,-1.5)(3.5,1.5)
\footnotesize
\psaxes[arrows=<->,ticks=none,labels=none](-3.5,0)(-4,-1.5)(3.5,1.5)
\psplot[linecolor=blue,plotpoints=100]{-3.5}{4}{cos(2*x)}
\psline[arrows=|-|,linecolor=red](-3.1415,1)(0,1)
\rput[b](-1.55,1.1){Periodo}
\psline[arrows=|-|,linecolor=red](0,-1)(0,1)
\rput[r](-0.1,0){\rotateleft{Amplitud}}
\end{pspicture*}